1. 支线：干线 trunk line; main line | 支线 branch line | 铁路专用线 railway special line
2. 岔线：section line 段管线 | branch line 岔线 | special line 特别用途线
3. 支管：branch line tester 支管测试器 | branch line 支管 | branch loop 分路<回路的一个分支
4. 分枝线：branch instruction 分枝指令 | branch line 分枝线 | branch of a curve 曲线的分枝
1. （铁路）支线
A branch line is a railway line that goes to small towns rather than one that goes between large cities.
1. Beijing unveiled three new subway lines including the airport line, line 10 and the Olympic branch line yesterday.
2. Another three lines and a branch line are now in construction and are expected to open to traffic in 2007 and 2008.
3. The west branch of Metro Line 2 goes to Xinjiekou and Hexi new city, and its east branch goes to Xianlin new town.
4. People waited in line at the HSBC's Mong Kok branch at around 7 am.
noun
1. a railway line connected to a trunk line
Synonym: spur track spur